Automated robots and robotic devices are becoming more prevalent today and are used to perform tasks traditionally considered mundane, time-consuming, or dangerous. As the programming technology increases, so too does the demand for robotic devices that can navigate around a complex environment or working space with little or no assistance from a human operator.
Robotic devices and associated controls, navigational systems, and other related systems are being developed. For example, U.S. Pat. No. 6,594,844 discloses a Robot Obstacle Detection System, the disclosure of which is hereby incorporated by reference in its entirety. Additional robot control and navigation systems, and other related systems, are disclosed in PCT Published Patent Application No. WO 2004/025947, and in U.S. patent application Ser. Nos. 10/167,851, 10/056,804, 10/696,456, 10/661,835, 10/320,729, and 10/762,219, the disclosures of which are hereby incorporated by reference in their entireties.
Many autonomous robots navigate a working space by simply moving randomly until an obstacle is encountered. Generally, these types of robots have on-board obstacle detectors, such as bump sensors or similar devices, that register contact with an obstacle. Once contact is made, command routines typically direct the robot to move in a direction away from the obstacle. These types of systems, which are useful for obstacle avoidance, are limited in their ability to allow a robot to track its location within a room or other working environment. Other systems, often used in conjunction with the bump sensors described above, use an infrared or other detector to sense the presence of nearby walls, obstacles, or other objects, and either follow the obstacle or direct the robot away from it. These systems, however, are also limited in their ability to allow a robot to navigate effectively in a complex environment, as they allow the robot to only recognize when objects are in its immediate vicinity.
In more advanced navigational systems, a robot incorporates an infrared or other type of transmitter. This transmitter directs a series of infrared patterns in horizontal directions around the robot. These patterns are, in turn, detected by a stationary receiver, generally placed at or near a boundary of the working space, on a wall, for example. A microprocessor uses the information from the signals to calculate where in the working space the robot is located at all times; thus, the robot can truly navigate around an entire area. These types of systems, however, are best employed in working spaces where few objects are present that may interfere with the dispersed patterns of infrared signals.
These limitations of the above types of navigational systems are, at present, a hurdle to creating a highly independent autonomous robot, which can navigate in a complex environment. There is, therefore, a need for a navigational system for a robot that can allow the robot to operate autonomously within an environment that may be cluttered with a number of obstacles at or near the operational or ground level. Moreover, a navigational system that can be integrated with some or all of the above systems (the bump sensors, for example) is desirable. Such a navigational system should allow a robot to recognize where it is at all times within a working area, and learn the locations of obstacles therein.